\documentclass{article}
\usepackage{amssymb,amsmath,amscd,concmath}
\pagestyle{empty}
\begin{document}
\begin{equation*}
	(<array align="c"> <item>
		&ldet;<array align="cc">
			<item>x<sub>11</sub>
			<item>x<sub>12</sub>
			<item>x<sub>21</sub>			
			<item>x<sub>22</sub>
		</array><rd>&rdet;
		<item> y <item> z
	</array>)
\end{equation*}
\end{document}
